Electric switch



March 27, 1951 c, THORPE 2,546,569

ELECTRIC SWITCH Filed Sept. 9, 1948 2 Sheets-Sheet 1 E. H. C. THORPE March 27, 1951 ELECTRIC SWITCH 2 Sheets-Sheet 2 Filed Sept. 9, 1948 [WWW l Fig.3

Patented Mar. 27, 1 951 12:.-

ELECTRIC SWITCH U Ernest Harry Charles Thorpe,.Kew Gardens, Englandgassignor to, C. A. V. Limited, London,

England Application September 9, 1948, Serial No. 48,482 In Great Britain September 25, 1947 1 Claim.

This invention has for its object to provide an improved manually operable electric switch of the kind having combined with it a delayaction device for controlling the rate of automatic return of the switchto its initial position after actuation, and more particularly a switch for controlling electromagnetically operated direction indicators on road vehicles.

In the accompanying drawings:

Figure 1 is a sectional side elevation, Figure 2 a plan (with actuating member removed), and Figure 3 a sectional plan of a switch embodying the invention.

Figure 4 is a plan showing the switch contacts.

In constructing in accordance with the invention a switch for controlling a pair of electromagnetically operated direction indicators on a road vehicle, and as illustrated by the accompanying drawings, a suitable body part a has mounted within it a pair of fixed contacts b situated at a convenient distance apart. Between these contacts are mounted a pair of resilient metal blades c carrying the movable contacts d. Between the blades is rotatably mounted an insulated cam 6 carried by a spindle which is operable by a finger piece 9, and adapted by its action on either of the blades to close the indicator circuit controlled by the contacts associated with that blade. Also on the spindle J carrying the said cam e is formed or secured a second cam h which co-operates with a pair of levers 12 arranged in alignment with each other, their free ends being adjacent and their opposite ends being pivotally connected to the body part.

The free ends of the levers bear on one end of a plunger 7' the opposite end of which is secured to a flexible diaphragm is. The latter divides an air chamber in the body part into two compartments m, n, one of which (m) may be permanently closed. The other (11.) is in communication with the outer atmosphere, or with another chamber 1', through a pair of valves. One of the valves has the form of a rubber sleeve surrounding radial holes 12 in a hollow boss n on the outer wall of the compartment n, and allows free out-fiow of air displaced from the compartment. whilst the other valve q (which is adjustable) serves to allow in-flow of air at a controlled rate. Preferably I employ a closed chamber r of ample capacity into which air is discharged and from which it is returned with the alternate actions of the diaphragm, so as to avoid risk oi. detriment to the action of the mechanism by dust-laden air.

The mode of action is as follows:

When the finger piece g is moved in either direction from its normal position, the two cams receive an angular movement. The first mentioned cam serves to close the circuit of the indicator to be brought into action, and the second cam by its action on the corresponding lever operates the diaphragm through the medium of the plunger. This movement of the diaphragm displaces air from one of the compartments and reduces the pressure in the other. After release of the finger piece, the switch is free to return to its initial position. This is effected by the return of air to the compartment from which the air was previously displaced, the rate of return being determined by the setting of the adjustable valve. The action of the returning air may itself be sufilcient to efiect the return movement, but if desired this action may be supplemented by a spring s which is compressed by the previous movement.

To bring the other indicator into action the finger piece is moved in the opposite direction, and then the diaphragm is actuated through the other of the two levers above mentioned.

Preferably I combine a signal lamp with the switch to give an indication of whether or not the indicator is in action. In the arrangement shown in Figures 1 and 2, I mount on a removable cover t of the body part a flash-lamp bulb holder u and a lamp contact piece '0, the bulb being indicated by w. The holder and contact are connected in parallel with a resistance a: to the switch contacts. The finger piece 9 is made wholly or in part from translucent material, or is provided with one or more windows, and is shaped to serve as a cover for the signal lamp.

By this invention a switch which is operable in one direction by hand and in the other direction automatically at a controlled rate can be provided in a very simple and convenient form. Whilst the invention is especially intended for controlling the circuits of a pair of directionindicators, it may be applied to other uses, and when it is required to control only a single circuit, a single movable contact member is provided, together with a single lever between the second cam and the plunger.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

An electric switch of the kind specified, comprising the combination of a manually rotatable actuating spindle, a pair of cams on said spindle, at least one movable switch member operable by one of said cams in response to rotary movement of said spindle, an air chamber, a, flexible diaphragm dividing said chamber into two compartments, a non-return outlet valve through which air from one Of said compartments can flow freely under the action of said diaphragm, an inlet valve through which air can enter the last mentioned compartment at a controlled rate, a plunger connected to said diaphragm, and at least one motion-transmitting leve arranged between one end of said plunger and the other of said cams, so that said diaphragm is operable by the last mentioned cam and serves to effect 4 return movement of said spindle to its initial position at a controlled rate.

ERNEST HARRY CHARLES THORPE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,491,712 Low Apr. 22, 1924 1,832,116 Heising Nov. 1'7, 1931 1,952,858 Haltrich Mar. 27, 1934 2,123,382 Rocher July 12, 1938 

